The Use of Glycerol-treated Homologous Pericardium as a Substitute for Cusps and Chordae Tendineae of the Mitral Valve in Sheep

In 11 weanling sheep chordae tendineae were replaced or a patch was implanted into the anterior mitral leaflet using homologous pericardium treated with 98% glycerol for 16.6 days on average. The sheep were electively sacrificed after 4, 6, 9, and 12 months. All animals showed competent mitral valves and good healing; only two sheep out of the patch-group showed small perforations at the suture line. Hemodynamic measurements and left ventricular angiography at rest and during stress test were normal except for the two cases. Histological examination revealed a distorsion and breakdown of pericardial collagen already after 4 months but the remnants of the graft were covered by a neointima of fibrous tissue. There were no signs of calcification and the new chordae tendineae and the patches were not shrunk, rigid or thickened. It is concluded that glycerol is a poor tanning agent, however, glycerol-treated pericardium seems to provide a lattice until fibrous tissue replacement has taken place. Therefore, we think it is a suitable material for mitral valve reconstruction.